Annie Dookhan was charged in September with obstruction of justice and falsifying her academic credentials. An assistant attorney general said at the time that the charges were "preliminary" and that a "much broader" investigation was being conducted.

On Tuesday, a Boston Municipal Court judge granted a motion filed by state Attorney General Martha Coakley's office asking that a pretrial hearing scheduled for Dec. 3 be rescheduled to Dec. 20. In the motion, prosecutors said the continuance was being sought because "a grand jury investigation is on-going with indictments expected" after Dec. 3.